Re: Ancient radiation levels were higher than today's levels

[Bernard L Cohen <blc+@pitt.edu>]

On Wed, 22 Dec 1999, Chris Davey wrote:

> > Bernard L Cohen wrote:
> > >         According to a forthcoming paper by Pollycove and Feinendagen,
> > > chemical and thermal effects cause 150,000 single strand breaks and 200
> > > double strand breaks per cell per day. By comparison, 10 rem of radiation
> > > causes 200 single strand breaks and 4 double strand breaks per cell. If
> > > double strand breaks are the source of cancer initiation, 10 rem of
> > > radiation per year causes 4 double strand breaks per cell per year which
> > > increases the number of cancer initiations by 4/200 = 2%. However,
> > > according to linear-no threshold theory, 10 rem of radiation per year
> > > increases one's cancer risk by 150% -- a very large discrepancy..
> > (snip)
> 
> Actually, 200 double strand breaks per day is 73000 per year, so 4
> more is only 0.005% more.  Hope I'm not missing something here...

	-I should have said that chemical and thermal effects cause 200
double strand break per cell per *year*, not per day. My apologies for
this carelessness and many thanks for catching this error.  Everything
else in my message is unchanged.


> 
Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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